s1_hello(){
 echo "hello, world!"
}
s2_tell_who_i_am(){
 echo "$(whoami)"
}
s3_which_distro_do_i_use(){
 if [ -f /etc/os-release ]; then
  . /etc/os-release
  echo "NAME=\"$NAME\""
 elif [ -f /etc/redhat-release ]; then
 DISTRO=$(cat /etc/redhat-release)
 echo "NAME=\"$(echo $DISTRO | awk '{print $1}')\""
 else "NAME=\"not find version mesage!\""
 fi
}
s4_view_my_cpu_arch(){
  local cpu_arch=$(uname -m)
  case "$cpu_arch" in x86_64|amd64)
  echo "x86_64"
  ;;
 *)
  echo "no find CPU:$cpu_arch"
  ;;
  esac
}
s5_show_first_scsi_disk_size(){
  disk_size_gb=$(lsblk -bno SIZE /dev/sd? --exclude 1 | tail -n +2 | awk 'NR==1{print $1/1024/1024/1024}')
  echo -n "${disk_size_gb%.*}"
}
s6_show_main_memory_size_in_megabytes(){
  free -m | grep "Mem:" | awk '{print $2}'
}
